Two basically identical Marshall 1960A cabs - totally different sound :/

[Setneck]

Hi!

Imagine two 1960A cabs from the same year (1996), so same speakers, same internal cables, same wood, aprox. same playing time, everything is totally the same. But both sound totally different.

One is very bright and in-front sounding, and the other is dark and dull, very muffled and muddy. The tone is like there's a blanket on the cab. I changed two upper speakers in that second cab for known good 75's - no change for better. The amp is Splawn Quickrod but similar impression was while using Bogner XTC.

What's wrong? Any solution for that second cab? Note that I want to keep the 75's there as their tone suits to what we play.

Thanks in advance, Andy

[Tone Meister]

The first thing I'd check would be speaker polarity. Many 4x12 cabs use a series/parallel wiring scheme with two pairs wired in series to double impedance, then paralleling the series pair at the input jack to bring total impedance back to that of the individual speakers. (e.g.; four 8-ohm speakers for total cab impedance of 8 ohms)

Check out this link and compare the correct diagram to your particular cabinet(s): http://www.jumbosunshade.com/swd01.htm

Hope this helps!

-Stan

[Setneck]

Thanks Stan I'll check the wiring and compare it with that brighter cab. Maybe one is series/Parallel and the second the opposite.

Regards, Andy

[whoismarykelly]

Are you guessing that they are identical or have you actually examined every detail to determine if they are? Are the back panels made of different materials? Are the jacks on both in good shape and making good electrical contact with the cable? Same grille cloth? Perhaps there is some minor detail that is altering the tone although I wouldn't think anything would be too dramatic other than the speakers themselves.

[Setneck]

I checked almost everything in both cabs and it seems that I have found the reason. Which is WOOD .

Yesterday I opened both cabs and checked the wiring and speakers. They were totally the same. The speakers have had even quite close serial numbers. After that , followed by the tip given by the other forum's user, I knocked a few times both cab's sides with the fist. And while one cab's box was responsing brightly the other's response was dull and muffled.

The difference in wood response is equal to the difference in overall sound. So the speakers and everything else is working fine. So now either I have to find other box or buy complete cab. Fortunately I have a good sounding specimen to compare with .

Thanks for everyone for help and tips

Regards, Andy

[solitaire]

Originally Posted by Setneck

I checked almost everything in both cabs and it seems that I have found the reason. Which is WOOD .

Yesterday I opened both cabs and checked the wiring and speakers. They were totally the same. The speakers have had even quite close serial numbers. After that , followed by the tip given by the other forum's user, I knocked a few times both cab's sides with the fist. And while one cab's box was responsing brightly the other's response was dull and muffled.

The difference in wood response is equal to the difference in overall sound. So the speakers and everything else is working fine. So now either I have to find other box or buy complete cab. Fortunately I have a good sounding specimen to compare with .

Thanks for everyone for help and tips

Regards, Andy

I think it's actually the construction of the dud cab and not the wood as such. These cabs are made at tremendous speed and are built using birch ply. Plywood as you know is spiral cut wood that's cross layered which makes for a very consistant material - though obviously there is going to be some variance there as well.

By 'construction' I mean how well executed the fingerjoints are and how the baffle and back-board were seated. Should you fail with the fingerjoints building a cab you can use the best wood available and it would still turn out a dud. Same holds true with hifi speakers and acoustic instruments.

[Setneck]

Maybe it is a matter of both things actually. That darker sounding cab is all original. And is wired correctly, nothing is out of phase (did battery test to the speakers). Everything was checked and compared with the other cab sounding correct. The other cab is just muffled and dull sounding, but not only from the speakers but also itself, while knocked with a bottom of screwdriver or fist. Maybe it is glued worse or something...

Next week I'll change the cab box for the other Marshall 1960A and will see what will happen to the tone.

Regards, Andy

[RocksOff]

I've noticed this effect on 2x12s if the back of one is screwed in either looser or tighter than another.